Aircraft construction



2 sheets-sheet i Dec. 21, 1937. R. B. GRAY ET Ax.

AIRCRAFT CONSTRUCTION Filed Deo. 2, 1956v Dec. 21, 1937. R. B. GRAY Er AL AIRCRAFT CONSTRUCTION Filed Deo. 2., 1956 2 Sheets-Sheet 2 INVENTORS. REID B. GRAY EDWIN I Zlvr ATTORNEY.

Patented Dee. 21, 1937 2,102,590 AIRCRAFT CONSTRUCTION Reid B. Gray, Dundalk, and Edwin L. Zivi, Baltimore, Md., assignors to The Glenn L. Martin Company, Baltimore, Mdi

Application December 2, 1936, Serial No. 113,173

9 Claims.

This invention relates to containers, and particularly containers for hydrocarbon substances. In its more restricted aspect it relates to aircraft construction and more particularly to an aircraft of improved construction for supporting and accommodating a novel container.

Tanks for containing hydrocarbons such as fuel and lubricating oils, and particularly such tanks for use in airplanes, in general have presented a 10 serious problem to the trade and various and sundry types of tanks have been proposed. All of the tanks heretofore proposed are undesirable for one or more reasons. The type of tanks now employed in the trade include a portion of the aircraft construction being formed and enclosed to provide a fuel compartment or tank and also metallic tanks which are separate from the aircraft structure and positioned within various parts of the aircraft, such as the fuselage, wing,

hull, and the like.

Metallic tanks of this nature, 'and especially such tanks when used in aircraft. whether they are built into the aircraft structure or formed separately and supported by the structure, present many undesirable features. For instance,

in the type of tank formed as a part of the aircraft structure, the seams connecting the adjacent parts of the tank ultimately become impaired to the extent of leakage of fuel through these seams or joints. These seams or joints are often impaired due to the stresses and strains under which the aircraft is subjected, such as landing, rough air, as well as weaving of the various parts during use. I'he separately constructed tanks aresubjected to objectionable vibrations together with the ever present difiiculties of constructing a metallic Vtank in such a manner as to prevent seepage of fuel by way of the rivets and other like means employed in the 40 construction of the tank.

All of the metallic tanks heretofore proposed are constructed of such material, which for some reason or other corrodes within the tank. This corrosion is probably due to electrolytic or gal- 45 vanic action set up by the introduction of foreign matter in the fuel. This foreign matter may be the result of improper straining of the fuel, or, possibly, condensation. Metallic tanks also present another problem in aircrafts of the fighting 50 type, as for instance, a bombingplane may be at an altitude of some 15,000 or 20,000 feet or ev-en much higher and for some reason or other it may be necessary to descend rapidly. In such cases the differential air pressure within the tank has 55 been known to explode the tank. This is, of

course, due to the improper venting of the tank, although suiiicient venting toVv take care of this radical change in air pressure may present other diillculties, such as the loss of fuel duringr acrobatic or fighting maneuvers. 5

Also, whether these metallic tanks are separate or formed as a part of the aircraft structure, it is necessary to disassemble that portion of the air,- craft in order to properly clean, inspect, repair, and replace such tanks. 10

Still another disadvantage of the metallic tanks heretofore proposed, is thatv when in case of a crash these tanks have a tendency to burst and throw the fuel over a large area of the plane which usually results in fire. 15

The invention broadly is directed to the provision of an improved container, particularly a container for hydrocarbons.

It is one object of the invention to provide an improved aircraft construction that shall over- 20 come the above difficulties.

Another object is to provide an improved fuel or lubricating oil tank for use in an aircraft.

Another object is to provide an improved aircraft construction that shall be adapted to sup- 25 port and accommodate a novel flexible container.

Another object is to provide an aircraft construction having a supporting structure for a flexible container that shall permit ready removal 30 of the flexible tank from the aircraft for cleaning, inspecting, repairing, and replacing.

Another object is to provide an improved container for use in an aircraft that shall be collapsible due to differential air pressures and which shall not burst in case it is subjected to a sudden impact or impacts.

Another object is to provide in combination with a metallic supporting structure a collapsible container that shall not corrode within and there- 40 by maintain a container free from such foreign matter.

Another object is to provide a novel collapsible container for an aircraft that shall be light in weight, durable, impervious to the fuels for which it is adapted to be used, and comparatively cheap to manufacture.

A further object is to provide an aircraft'construction having the above characteristics, wherein the said flexible container is of such novel construction that shall render it impervious to fuel, such as gasoline, lubricating oils, and the like, and which may be readily repaired in case of a. puncture due to a bullet, or the like.

A still further object is to provide novel means prevent seepage of fuel through the seams connecting adjacent tank walls.

` containing any fluid 'required in aircraft such ask taken from the interior of Figure 7.

The above and other objects will be made apparent through the further` description of the invention when taken in connection with the accompanying drawings, wherein like reference characters refer to like parts. It is to be distinctly understood that the herein described container is not only adapted for use with fuel and lubricating oil, but is intended to be employed for water and gas. The drawings are not a definition of the invention, but illustrate a manner in which the invention may be eiiectuated. The inn ventionis defined by the appended claims.

In the drawings: Figure 1 is a fragmentary top plan view of an aircraft illustrating one embodiment of the in` l vention. Y

Figure 2 is a sectional, view taken along the line 2 2 of Figure 1. Figure 3 is a sectional view taken along the line 3 3 of Figure .1.

Figure 411s a sectional view taken along the lined-4 of Figure 1.

Figure 5 is a fragmentary view in elevation Figure 6 is a sectional view taken `along the line G Bof Figure 4. Y ,f

Figure 7 is a top plan view'of a collapsible fuel tank embodying the invention.

a detail of the invention.

villustrated two separate and like fuel containing means each representedin its entiretyy by I2.

'I'he means I2 comprises a collapsible leakproof inner tank I3 (seeFigure '7) and the associated wing structure arranged to support the collapsible tank I3.

For the sake oi' simplicity and claritythepresent hinvention is illustrated in connection with the wing structure. However, it is to be distinctly understood that the present fuel conlage of an airplane, hull or seawings of a ying boat, or any other part of the aircraft which is suitable or desirable. f

In the form showrfthe wingII consists of a framework comprising conventional beams or `spars I4y spacedapart and' extending lengthwise of the wing. 'I'hese spars are connected together by means oi' ribs or transverse members I5 and form a frame structure coveringrepresented in its entirety by I 6.

'I'he tank may be ofv such size and capacity as may be required for the 'particular installation enlargedv fragmentary sectional l sectional'view taken along the kpertinents from the manhole 2i.

a sectional view taken along the' for supporting a wing 2,102,590 -for constructing a flexible container that shall I and as shown, the fuel containing means I2 is located within the structure of the wing I I and adjacent the fuselage II). The fuel containing means I2 is positioned intermediately of the wing I I and within the confines of the first four ribs or upper and lower transverse members I5 nearest Y the fuselage and the cooperating spaced spars Il. The upper and lower inner ribs I5 are connected by a partition I1, the latter serving to close this end of a supporting structure represented in its entirety by I8 for the collapsible tank I3. 'I'he web of the spars Il constitutes the sides of the supporting structure I8 and apartition I9 conanecting the upper and lower outer spars I5 provides an outervend for the supporting, structure I8,the covering I6 serving as the top and the bottom of the supporting structure I8.

'I'he bottom of the supporting structure is provided with an opening or manhole 2I and is preferably positioned to communicate with theinterior of the supporting structure I8 and at a point in the center thereof, as for instance, be?- tank I3 within the supporting structure I 8.

For the purpose of reducing the agitation of the fuel within the fuel containing means I2, bulkheads 22 are provided within the supporting structure I8 and preferably connected to the upper and lower transverse rality of compartments within structure I8. These bulkheads are formed to provide an opening 23 therethrough suiiiciently faces of the transverse members ings 23 are preferably provided with a bead 26 (as best shown in Figure 9). 'I'hese beads`26 operate to receive the cooperating portionsof the bulkheads25 and present a smooth round surface for eliminating wear due to friction.

It can now be understood that the collapsible .tank I3 may be positioned within the tank supporting structure I8 by way of the manhole 2| and openings 23 within the Vbulkheads 22. Novel means is provided for supi The inner sur-y I5 as wellas ther bulk heads 25 and 22 of the tank I3 and supporting structure I8, respectively, and as here shown the vents 21 comprise a tubular-member extending y through the surfaces of these cooperating. bulkheads and connetting the adjacent compartments. Drains 28 positioned through the cooperating bulkheads 25R and 22 and adjacent the bottom thereof are provided for connecting the adja-v cent compartments and maintaining a common level therein. A suitable fuel inlet 29 and outlet 3l is provided and connected with the assembled collapsible tank I3 and supporting structure I8. The inlet 29` may be assembled in any leakproof manner to permit the filling of the tank I3, while novel means Vis provided for connecting the outlet 3I with the 'collapsible tank I3. The outlet 3l may comprise a tubular member 32 Aextending through adjacent lower surfaces of the inner end I1 of the supporting structure I8 and the cooperating part of the tank I3.

Located within the tank I3 is a tubular member 33 having an annular outwardly extending fiange 34 adapted to conform with the associated contour of the inner surfaces of the tank' I3. The tubular member 33 as well as the flange 34 is molded from material similar to that which the tank I3 is composed of. This material, of course, is impervious to fuel and will be later described. The flange 34 of the tubular member 33 is fixed to the associated kinner surfaces of the tank I3 in a positive leakproof manner and in order to strengthen this particular portion of the assaciated mechanism, an additional strengthening piece 35 is applied to the associated outer surface of the tank I3, and the three elements, namely flange 34, tank I3, and strengthening piece 35 are preferably cemented as well as sewed into firm fixed relation. A suitable clamp36 may beemployed for clamping the tubular member 33 into a leakproof contact with the outer surfaces of the tubular member 32.

The drains 28 as well as the vents 21 are assembled in leakproof relation similar to that described in connection with the outlet 3|. Each of theidrains 28 and the vents 21 include a tubular member 31 and cooperating oppositely disposed tubular members 38 about the ends of the tubular members 31. Each of the tubular members 38 include integral flanges 39 formed to cooperate with the adjacent contour of the inner surfaces of tank I3.

In this construction the fianges 39 are fixed to the opposite sides of the split bulkheads 25 of the tank I3 preferably by gluing and sewing and also the lower portion'of the flanges 39 are connectedA to the adjacent inner bottom surfaces of the tank I3. As here shown tank I3 is constructed'to overlap as shown at 4I and the cooperating portion of flange 39 is sewedv as well as glued to this fiat portion 4I providing a rigid leakproof connection. Each of fthe tubular members 38 are connected to the cooperating end of tubular members 31 by means of sui/table.

clamps 42.

The bulkheads 25 of the tank I3 are formed by initially constructing the several compartments of tank I3 separately. This provides a novel construction of the bulkheads 25 for receiving the bulkheads 22 in the supporting structure I8. This is effected by the construction of bulkheads 25 of the tank I3, which construction consists of adjacent bulkheads 43 `of the adjacent compartments beingy connected together at the edges of the openings in the bulkheads 25 corresponding to the openings 23'` in the bulkheads 22. Y The adjacent members 43 are preferably connected by a pair of annular overlapping members '44 adapted to receive the cooperating edges of the members 43 and arecemented and sewed in firm fixed relation one with the other to form ,a positivev leakproof connection.

In addition to the support aiorded by the.

drains 28 and the vents 21 ofA the'tank I3 suitable hooks (see' Figure 6) may be carried by the inner surfaces of thesupporting structure Il and adapted to engage a cooperating flap 48 carried by the adjacent surface of the tank I3.`

Reinforcing means 41 are carriedfby the tank I3 and positioned to protect the tank from damage by any contact with orfriction against the hooks 45. Another means may be provided for supporting the tank I3 within the structure I8 instead of thev hooks 45 and flaps 46. This means is best illustrated in the left upper corner of Figure 4, wherein there is provided a lug or projection 56 molded from neoprene or a like composition. This lug 56 is provided with 4an integral flange 51 adapted to lie flush with the cooperating contour of the associated surface of the tank I3 and is fixed thereto in a similar manner to that described in connection with flanges 34 and 39 of the tubular members 33 and 38,

respectively.

A' suitable covering 48 for the manhole 2I as well as the cooperating opening 2l in the tank I3 is provided for connecting the associated surfaces of the tank I 3 in leakproof relation with the covering and the cooperating bottom of the supporting structure I8. This covering 48 also constitutes an additional support for the collapsible tank I3 within the supporting structure I8 and as here shown the Vcovering 48 comprises an inner and outer member 49 and 5I, respectively, adapted to receive the cooperating portion of tank I3 and the bottom I8 of the supporting structure I8 andA clamp them into rigid leakproof relation. This is accomplished by suitable vdetachable connections such -as bolts 52 having positive lock nuts,53. The inner member 49 is annular in shape (see Figure 13) and is preferably provided with an additional reinforcing member 54 adapted to lie between the member 49 and the associated surfaces of the tank I3 so that the bolts 52 will operate to clamp the several cooperating members into rigid leakproof relation.

The inner tank is constructed of flexible material impervious to the liquid or gas that it is intended for use. This material may be ofY any suitable composition that will satisfactorily flll the oiiice for .which it is intended. As a preferred embodiment there is here employed a fabric treated with a compound known in the trade as neoprene. This compound may be described as a synthetic rubber product, as it is difficult to observe any physical difference. However, the present compound is distinguished by the fact that it is impervious as well as resistant to the deteriorating action of crude petroleum oils 'or fuel used in internal combustion engines.

This compound when applied to a fabric provides a material that is not only impervious to the 4fluid for which it is intended to be used, but it is exceptionally light in Weight, the latter being usv supporting structure Il,

instaustionrorwnienne anni intended. 'nin neopreneproduct is ofthe required possessed strength and durability Itwithstand the strainsl for use to which -the inner tank is lsublected.

y The tubular member of the outlet'means as ther reinforced by reinforcing members 4I (see IFigure'I). 'lhemembers Il may'be andln'ef-` erably are constructed of the same product as the tank, although the thickness of the members Il may be greater thanthe thickness of the ltank if proper. niese reinforcing members prevent the tank from giving away at the corners where the adiacent vsurfaces of the-tank are positioned for contact with each other and subiectedto additional friction and wear than the tank proper. For the purpose of transferring the weight of the fuel within the collapsible tank Il to the the inner tank is constructed so that its overall dimensions are greater than the corresponding inner dimensions of the supporting structure i8.I This is an important feature of this invention and this feature provides a number `of vital characteristics required to overcome the difficulties heretofore presented by previous fuel containing means. Some of. these advantages are: In addition to transferring the load of the structure Il. the tank will readily expand or col- Ipse due to differential air pressures. Also incase of a sudden impact such as a crash. this improved tank constructionv willy not burst and throw gasolineor its contents over a large area, but instead it will at the worst merely tear and permit the fuel passing out through such opening to be more or less-localised to the region of the tank.

Figure 5 illustrates another feature of the invention. wherein novel means is provided for positively preventing any seepage of the fuel by way of the' seams and stitches `employed in the construction of the collapsible tank. This' means comprises impregnating the stitching with a neoprene or like composition and then incovering the seams and stitches with a strip or sheet Il which is preferably made from a thin sheet of neoprene composition. This strip orsheet tl is positioned on the inner side.of the tank I8 and glued over the adjacent surfaces to the seams indicated at l2. By placing this strip Il on the interior of the tank. the pressure or weight of the fuel operates to press the strip 4against the adjacent surfaces to the seams and augments the sealing of the seams against access to the fuel. This strip or sheet 8| may be employed wherever such seams 02 occur within the tank I 3.

'Ihesestrips or sheets OI may be made from neoprene composition or similar material with or without the use of an inner fabric.

Accordingly, there is provided in improved aircraft construction including a novel 'containing' means that shall operate emciently and to'overcome the difficulties heretofore encountered with the previously proposed containing means.'

While this invention has been illustrated andA described in connection with a monoplane wing, it is to be distinctly understood that the principles here disclosed are equally adaptable' for use with airplanes or nying the containing boats or other types and that '1. A petroleum containing means be molded'v in the abthe collapsible tank Il'are furcapacity than thel aircraft. ya structural portion having 2o a reinforcing member arranged therein, saldi mei to vthe supporting 'providing communication. of the two-ply partition therein means may be positioned at any` rigid supporting enclosureand a closure positioned within said closure,` the outer dimensions of the said lapsible enclosure being greater than the inner dimensions of the said supporting enclosure..

2.;An aircraft taining means. the said means comprising a rigid .3. In an structure yforming an enclosure, said`reinforcy havingjan aperture therethrough.l and a hydrocarbon container formedof a pliant material impervious to gasoline arrangedwithin said structure. of said reinforcing member and having a partition therein oolrelionding to said reinforcing member, and

outer dimensions said enclosure.

4. In an airplane having a wing. and having a reinforcing member extending transversely of including a en-y construction including a con4 structure having a collapsible said container lying on both sides' said ming, lsaid reinforcing member having an aperture therein, a hydrocarbon containing tank comprised of a pliant material impervious `to gasoline having portions loca on both sides of said reinforcing member and having a partition corresponding to said reinforcing meniber provided with an aperture corresponding to the aper'- ture in said reinforcing member. said aperture between the portions tank on opposite sides of said reinforcing member. v .L i -5. In an'aircraft, a-liquid hydrocarbon conf tainer comprising a rigid framework and a collapsible container of a pliant material secured' at a plurality of points within said. framework and vhaving its outer dimensions greater than the inner dimensions of said framework. y 6. In an aircraft, a liquid hydrocarbon container comprising a rigid frame having a partition therein, saidl partition having an aperture therein, yand a exibile container impervious -to liquid lwdrocarbons-within said'frame having a two-ply partition therein providedwith an aperture corresponding to said ilrst aperture, the plies of said second partition lying on opposite/sides of the i'irst partition and. being sealed together at the common apert said flexible container having greater' outer dimensions than the inner dimensions of said frame.

7. In an aircraft, a liquid hydrocarbon container comprising a rigid frame having-a partition therein. said partition having an aperture therein', and a flexible container impervious to' liquid hydrocarbons within said frame having a ture corresponding to said iirst' aperture, the

sides of the first partition and being sealed together at the common aperture. i

provided with an aperplies of said second partition lying on opposite lns communicating compartments, the plies of said 8. In a device as claimed in claim '1, means mounting said exible container in said rigid frame including a vent passing through said whereby said container may be mounted in a rigid partition.

. 9. A liquid hydrocarbon container for vehicles comprising a ilexible container of pliant material impervious to liquid hydrocarbons and having a two-ply partition therein provided with an aperture and thereby dividing the container into partition being -sealed together at the edge of said aperture and being otherwise separate,

partitioned frame forming part of a vehicle with said partition of the container enclosing a par-4 tition of the rigid frame.

. REID IB. GRAY.

EDWIN L. ZIVI. 

